The present invention relates to a phase change recording medium and to a method for recording in and reproduction from the recording medium, and more particularly to arts of a phase change recording medium and a method for recording in and reproduction from the recording medium to attain high-density recording.
The phase change recording media are those which use, as a recording film, materials exhibiting a reversible between a crystal state and an amorphous state. Chalcogenide materials are known as materials used for recording films of such phase change recording media. Examples of such chalcogenide materials include a GeSbTe-type, InSbTe-type, InSe-type, InTe-type, AsTeGe-type, TeO.sub.x -GeSn-type, TeSeSn-type, SbSeBi-type, BiSeGe-type and AgInSbTe-type.
A general phase change recording medium is of the disk shape. It is provided with a guide concave and convex sections formed on a substrate. The projections (convex sections) and the concave sections are termed the land and the groove respectively.
With recent development of highly densified phase change recording media, the land-groove recording system has been proposed in which records are written in both of the land and groove. In this land-groove recording system, the distance between the recording marks which are adjacent to each other is small and hence the problem (cross-erasure) arises in which the adjacent marks which have been recorded are erased in the recording step.
JP-A-124211/1996 discloses an art which can solve this cross-erasure.
This art, however, requires to make the film thicknesses of the land and groove different from each other, which is troublesome in the production of the medium and hence uneconomical.